Interlocked pin bottom



Ndv. 11, 1969 F. E. SATCHELL ET AL 3,477,721

INTERLOCKED PIN BOTTOM Original Filed Jan. 17, 1966 INVENTORS, l7 FRED E. SATCHELL ANTON w. RYTlNA l6 LOUIS .1. TRIER ATTORNEYS United States Patent 3,477,721 INTERLOCKED PIN BOTTOM Fred E. Satchell, Chesterfield, M0., and Anton W. Rytina,

Grand Haven, and Louis J. Trier, Muskegon, Mich., assignors to Brunswick Corporation, a corporation of Delaware Continuation of application Ser. No. 520,974, Jan. 17, 1966. This application Oct. 9, 1968, Ser. No. 772,450 Int. Cl. A63d 9/00 US. Cl. 273-82 6 Claims ABSTRACT OF THE DISCLOSURE A pin bottom for use in combination with a bowling pin which has a central reduced shank at its butt end formed by an undercut at the juncture of the bottom surface and side surface of the pin, with the undercut BACKGROUND OF THE INVENTION This is a continuation of our copending application Ser. No. 520,975, filed I an. 17, 1966 and now abandoned.

One of the main disadvantages of most commercial bowling pins is their relatively short life resulting from damage caused by one pin striking another or striking the bowling alley. One of the parts of a bowling pin most susceptible to such damage is the butt end, especially the corner portion of the pin which forms the juncture between the bottom and side surfaces of the pin. As a result, most commercial pins are now made with a wearresistant base member which is positioned in an annular recess at the juncture between the bottom and side surfaces of the pin. The fall-out these base members is a continuing problem in the bowling field, and there have been many attempts of locking the base member in place. Structural adhesives have been used, but have been unsatisfactory because the bond between the base member and the pin is destroyed as the result of hooping type flexures which are caused by a blow against the side of the base member. Another attempt has included postforming thermoplastic materials in the recess to form a base member interlocked to the bowling pin itself. But such methods have proven unsatisfactory because the same hooping type flexure breaks the interlock. Other attempts have included the provision of a two-piece mechanically interlocked base member having a wear-resistant outer shock member and a flexible inner member. It is most desirable to adhesively bond the flexible inner member to the pin, but because the inner member is usually exposed to the hooping stresses, the bond is rapidly broken. Attempts have been made to mechanically interlock the flexible inner member to a projecting shank portion of the pin by forming an annular cut or groove in the shank portion into which a lip or bead on the flexible inner member extends to mechanically interlock the inner member to the shank portion and obviate the necessity of adhesives. Such means have proven unsatisfactory because the cut formed in the shank portion causes a stress riser. More particularly, the annular cut causes an abrupt change in the area of the impact zone where the hooping stresses are most pronounced. The stresses 3 ,477,721 Patented Nov. 11, 1969 are disproportionately high at that point and the pin is prone to crack or split. This invention is directed to solving this dilemma.

SUMMARY OF THE INVENTION It is the principal object of this invention to provide a new and improved pin bottom for protecting the butt end of a bowling pin, and a method of fabricating the same.

It is another object of this invention to provide a pin bottom of the character described wherein an inner flexible member is remote from the impact zone and therefore unexposed to hooping stresses with the flexible member permitting limited axial movement of an adjacent base member.

It is another object of this invention to provide a pin bottom of the character described wherein the inner flexible member is removed from the stress area whereby a high tensile adhesive may be employed to bond the flexible member to the pin rather than the very soft low tensile materials which must be used when the inner member is exposed to stress.

It is still a further object of this invention to provide a method wherein the inner flexible member is molded in place between a prepositioned outer impact member and the bottom of a recess in the bowling pin, thereby creating a tight bond between the inner member and the bowling pin itself.

Other objects and advantages will become apparent from the following detailed description taken in connection with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIGURE 1 is a partial central sectional view through the base of a bowling pin illustrating the annular groove or recess into which the base member of this invention is positioned;

FIG. 2 is a partial sectional view through the base of a bowling pin illustrating one embodiment of the invention;

FIG. 3 is a partial sectional view through the base of a bowling pin illustrating a second embodiment of the invention;

FIG. 4 is a partial sectional view through the base of a bowling pin illustrating a third embodiment of the invention;

FIG. 5 is a partial sectional view through the base of a bowling pin illustrating a fourth embodiment of the invention; and

FIG. 6 is a partial sectional view through the base of a bowling pin illustrating means facilitating the method of this invention prior to inserting the settable plastic inner base member.

DETAILED DESCRIPTION OF THE INVENTION While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail an embodiment of the invention together with modifications thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiments illustrated. The scope of the invention will be pointed out in the appended claims.

The invention is illustrated herein in combination with a bowling pin 10 having a central reduced outwardly projecting shank 11 at its butt end. The shank 11 is formed by an undercut at the juncture of the bottom surface 12 and the side surface 13 of the pin. The undercut extends into the body of the pin adjacent the shank 11 forming a downwardly facing annular groove or recess 14 into which the novel pin bottom of this invention is positioned. In

Wooden bowling pins, the undercut or groove may be formed by turning. In aluminum or synthetic bowling pins, the undercut or groove may be molded directly with the pin. Like numerals will be employed throughout the drawings and specification to indicate like parts in the various embodiments shown.

The novel two-piece interlocked pin bottom of this invention is generally comprised of a flexible upper base member 15 and a wear-resistant lower base member 16. The flexible upper member 15 is the bonding member and embraces the shank 11 of the pin entirely at the uppermost areas of groove 14. The wear-resistant lower member 16 is the impact member and extends at its upper end into groove 14 and terminates at its lower end in a shoulder 17. The shoulder forms a continuation of the bottom surface 12 and side surface 13 of the bowling pin. The upper member 15 may be secured tightly in the groove 14 by a high tensile adhesive. The two base members 15 and 16 are mechanically interlocked by a means, generally designated 18 and described below, to releasably secure the lower member 16 to the upper member 15 with the upper end of member 16 positioned in groove 14. The flexible upper member 15 is formed of a vinyl or other soft material and the lower member 16 is formed of a nylon or other wear-resistant material. Between the two surfaces 13a and 17a is an annular space S. The resilience of flexible member 15 and space S permit limited upward axial movement of the lower base member 16 relative to the pin without compression of the pin.

It can readily be seen that the flexible upper bonding member is completely remote from the impact zone. Thus, when the impact member is struck by blows approximately in the direction of arrows A, FIG. 2, the nylon impact member will hoop and move in an axial direction in normal fashion, thereby absorbing the impact of the blow and protect the bowling pin. However, the vinyl or other soft material which forms the flexible member 15, being discontinuous from the nylon member 16, will not be exposed to the stresses created by base member 16. A high tensile adhesive bonding the flexible member to the bowling pin will therefore not be affected in any manner. In fact, a direct blow in the direction of arrow B, FIG. 2, would likewise have no effect on the high tensile adhesive between the bottom of the groove 14 and the innermost surface 19 of the flexible member 15. The flexible member 15 thus provides a hinged joint for the impact member 16 and yet it may yield to some slight stress encountered without affecting the strong adhesive bond between it and the bowling pin.

FIGS. .2 through 5 illustrate various embodiments of the hinge means 18 mechanically interlocking the impact member 16 to the flexible member 15. FIG. 2 shows an embodiment wherein an annular securing head 20 is formed integral with the impact member 16 at its upper end. A corresponding annular securing groove 21 is molded integral with the flexible member 15 to receive the securing head 20 and mechanically interlock the two members.

The embodiment of FIG. 3 is a reverse of the hinge means shown in FIG. 2 in that an annular securing bead 22 is molded integral with the flexible member 15 and a corresponding annular securing groove 23 is molded integral with the impact member 16 to provide a mechanical interlock for the two members.

FIG. 4 shows an embodiment wherein the flexible member 15 is provided with an outer laterally extending lip 24 which is spaced from the body of the flexible member to form an annular lip receiving recess 24a, and the impact member 16 is provided with a complementary inner lip 25 which forms a corresponding lip receiving annular recess 25a to provide complementary interengaging surfaces 26 on the respective members to provide a mechanical interlock therefor.

The embodiment illustrated in FIG. 5 is similar to that shown in FIG. 4 but the lips 24 and 25 are provided with camming surfaces 27 and 28 to facilitate assembly while providing the complementary interengaging surfaces 26 to mechanically interlock the two members together.

The two members are preferably assembled prior to their insertion into groove 14 whereby structural adhesive may be applied to the outer surfaces of the flexible member 15 and the entire assemblage, comprised of the flexible member 15 and impact member 16, may be inserted into groove 14 and then tightly pressed against the pin in the direction of arrof B, FIG. 2, whereby the adhesive will tightly adhere to the bottom and/or sides of groove 14.

It can be seen that suflicient flexibility in the flexible member 15 would facilitate replaceability of the impact member 16 should the impact member become damaged. For instance, the walls of the annular securing groove 21, in the embodiment illustrated in FIG. 2, could be deformed to permit the securing head 20 to be removed from groove 21 to facilitate replacement of the impact member 16. Likewise, suflicient flexibility in member 15 will permit deformation of the appropriate portion thereof in the embodiments illustrated in FIGS. 3 through 5 to permit replacement of the impact member 16.

FIG. 6 illustrates a means whereby the principle and objectives of this invention can be accomplished in a method of fabricating a pin bottom for bowling pins wherein the upper flexible member 15 is molded in position within groove 14. The preferred method includes the steps of forming a recess or groove extending into the body of the pin member 10 at the juncture between the bottom surface 12 and side surface 13 of the bowling pin, as above described and as illustrated in FIG. 1. The impact member 16 is then positioned in the recess 14 spaced from the bottom of the recess as illustrated in FIG. 6. The next step includes the insertion of a settable resilient material of the plastic type into the space between the impact member and the bottom of the recess. The material may be a thermosetting material, such as flexible epoxy or urethane, and could obviate the use of adhesives since such materials develop high adhesive strength in adhering to the preferably wooden bowling pin. To facilitate insertion of the plastic material, the material may be poured through a passage 30 drilled from the center of the shank 11. The material is poured to completely fill the remaining space in the annular groove 14 and effectively interlock the impact member 16 within the groove on setting of the material. The passage 30 may also be filled with the plastic material, or other appropriate substitutes to avoid stress risers, as above described. A similar passage may extend vertically upwardly through the impact member 16 to facilitate insertion of the plastic material.

The plastic material may be placed into the bottom of groove 14 prior to positioning the impact member 16 therein. For instance this may be accomplished by turning the pin upside down.

By molding the inner flexible member 15 in position within the space between the impact member 16 and the bottom of the groove 14, the problem of maintaining correct tolerances between the two members is completely obviated. The tolerances are critical since the shoulder 17 forms a continuation of the bottom surface 12 and side surface 13 of the bowling pin. It is highly undesirable to have abrupt changes in this preferably smooth continuation.

Thus it can be seen that we have provided a new and improved bowling pin having a novel two-piece protective base member wherein the bonding member is unexposed to the impact zone thereby permitting the use of high tensile adhesives creating a tight bond and eliminating fall-out of the base member without creating stress risers.

We claim:

1. In combination with a bowling pin having a central reduced outwardly projecting shank at its butt end, said shank being formed by an undercut at the juncture of the bottom surface and the side surface of the pin, said undercut extending into the body of the pin adjacent said shank forming a downwardly facing annular groove, a pin bottom comprising: a flexible upper base member embracing said shank and positioned entirely at the uppermost areas of said groove and bonded thereto; a wearresistant lower base member of a relatively rigid material as compared to said flexible upper base member, extending at its upper end into said groove and terminating at its lower end in a shoulder; and means mechanically interlocking said upper and lower base members to form the pin bottom and to releasably secure said lower base member on said bowling pin, said upper base member interlocking means having suflicient resiliency to permit the release of said lower base member, and means permitting limited upward axial movement of said lower base member relative to said pin in use without compression of the pin.

2. The bowling pin of claim 1 wherein the shoulder of said lower base member forms a continuation of the bottom and side surfaces of the bowling pin.

3. The bowling pin of claim 1 wherein said last-named means includes complementary interengaging surfaces on said base members to mechanically interlock said base members.

4. The bowling pin of claim 1 wherein said last-named means includes an annular securing bead on one of said base members and a corresponding annular securing groove on the other base member receiving said securing bead to mechanically interlock said base members.

5. The bowling pin of claim 1 wherein said flexible base member is bonded in said groove by a structural adhesive.

6. In a bowling pin of the type having means defining a bottom surface and a side surface, a protective pin bottom comprising: a recess extending into the body of the bowling pin adjacent the juncture between the bottom surface and side surface thereof; an inner flexible member positioned entirely at the bottom of the recess and bonded thereto; and an outer impact member of a relatively rigid material as compared to said flexible inner member, including means mechanically interlocking the outer member to the inner member to form the pin bottom, said outer member having a thickness substantially equal to the width of the recess and shaped to define a continuation of the bottom and side surfaces of the bowling pin, said upper member interlocking means having sufiicient resiliency to permit the release of said lower member, and means permitting limited upward axial movement of said lower member relative to said pin in use without compression of the pin.

References Cited.

UNITED STATES PATENTS 2,680,023 6/1954 Ellis 273-82 2,701,719 2/1955 Di Pierro 273-82 2,809,038 10/1957 Scheidemantel et al. 273-82 3,232,615 2/1966 Faulkner 273-82 RICHARD C. PINKHAM, Primary Examiner R. J. APLEY, Assistant Examiner 5 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3-477 721 Dated Nrlvember ll- 1969 Invent fls) F. E. Satchell, A. W. Rvtina and L. J. Trier It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

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